Support for extensions using XUL/XPCOM or the Add-on SDK was removed in Firefox 57, released November 2017. As there is no supported version of Firefox enabling these technologies, this page will be removed by December 2020.
Add-ons using the techniques described in this document are considered a legacy technology in Firefox. Don't use these techniques to develop new add-ons. Use WebExtensions instead. If you maintain an add-on which uses the techniques described here, consider migrating it to use WebExtensions.
Starting from Firefox 53, no new legacy add-ons will be accepted on addons.mozilla.org (AMO) for desktop Firefox and Firefox for Android.
Starting from Firefox 57, only extensions developed using WebExtensions APIs will be supported on Desktop Firefox and Firefox for Android.
Even before Firefox 57, changes coming up in the Firefox platform will break many legacy extensions. These changes include multiprocess Firefox (e10s), sandboxing, and multiple content processes. Legacy extensions that are affected by these changes should migrate to use WebExtensions APIs if they can. See the "Compatibility Milestones" document for more information.
A wiki page containing resources, migration paths, office hours, and more, is available to help developers transition to the new technologies.
AddonListeners can be registered with addAddonListener()
and will then receive notification of changes to the add-ons currently installed. These notifications come in the form of calls to methods on the listener object. A listener only needs to implement the methods corresponding to the events it cares about; missing methods will not cause any problems.
void onEnabling(in Addon addon, in boolean needsRestart) |
void onEnabled(in Addon addon) |
void onDisabling(in Addon addon, in boolean needsRestart) |
void onDisabled(in Addon addon) |
void onInstalling(in Addon addon, in boolean needsRestart) |
void onInstalled(in Addon addon) |
void onUninstalling(in Addon addon, in boolean needsRestart) |
void onUninstalled(in Addon addon) |
void onOperationCancelled(in Addon addon) |
void onPropertyChanged(in Addon addon, in string properties[]) |
Called when an add-on is about to be enabled.
void onEnabling(
in Addon
addon,
in boolean needsRestart
)
Addon
that is being enabledCalled when an add-on has been enabled.
void onEnabled(
in Addon
addon,
)
Addon
that has been enabledCalled when an add-on is about to be disabled.
void onDisabling(
in Addon
addon,
in boolean needsRestart
)
Addon
that is being disabledCalled when an add-on has been disabled.
void onDisabled(
in Addon
addon,
)
Addon
that has been disabledCalled when an add-on is about to be installed.
void onInstalling(
in Addon
addon,
in boolean needsRestart
)
Addon
that is being installedCalled when an add-on has been installed.
void onInstalled(
in Addon
addon,
)
Addon
that has been installedCalled when an add-on is about to be uninstalled.
void onUninstalling(
in Addon
addon,
in boolean needsRestart
)
Addon
that is being uninstalledCalled when an add-on has been uninstalled.
void onUninstalled(
in Addon
addon,
)
Addon
that has been uninstalledCalled when a pending operation for an add-on is cancelled.
void onOperationCancelled(
in Addon
addon,
)
Addon
that has had a pending operation cancelledCalled when one or more properties of Addon
has changed.
Only applies to the following properties:
void onPropertyChanged(
in Addon
addon,
in string properties[]
)
Addon
that has had its properties changed